Various types of connector for use in such an application have already been proposed.
One of them is a connector with rotary coupling as described in U.S. Pat. No. 4,943,188 and U.S. Pat. No. 4,907,914. Coupling is obtained by a downward movement and then an upward movement during which sloping surfaces of a receptacle of the connector cause the male portion to turn on its axis, thereby enabling connection fingers to lock in complementary elements of the receptacle.
That type of connector presents various drawbacks, including its size and the complexity of making it industrially.
Connectors also exist that do not turn during connection, in particular the ball-type connectors as disclosed in U.S. Pat. No. 4,643,472. That connector makes use of the well-known principle of balls locking against ramps. The male portion comprises a shaft with sloping regions that is surrounded by a cylindrical sleeve presenting holes that face the sloping regions of the shaft, a respective ball being housed in each of these holes. Locking is obtained by the fact that the balls become jammed against the sloping surfaces. Locking or unlocking of the balls, and thus of the connector, is achieved by moving the cylindrical sleeve axially in order to lock or release the balls.
The problem posed by that type of connector is that although connection and disconnection operations are made easier compared with rotary-coupling connectors, docking requires precision alignment that is not easily obtained in the intended application, and bending stresses are not accommodated and may lead to a large amount of fatigue in the risers.